In this handout photo from the University of Bergen taken on Tuesday, Jan. 31, 2017, researchers from the university begin dissecting a two-ton whale that was beached in shallow waters off Sotra, an island west of Bergen, some 200 kilometers (125 miles) northwest of Oslo. Norwegian zoologists have found about 30 plastic bags and other plastic waste in the stomach of a beaked whale that had beached on a southwestern Norway coast. Terje Lislevand of the Bergen University says the visibly sick, 2-ton goose-beaked whale was euthanized. Its intestine "had no food, only some remnants of a squid's head in addition to a thin fat layer." (University of Bergen via AP)

Lislevand says the non-biodegradable waste was "probably the reason" why the male whale repeatedly beached last Saturday in shallow waters off Sotra, an island west of Bergen, 200 kilometers (125 miles) northwest of the capital of Oslo.

It's size - about 6 meters (20 feet) - showed the whale was an adult. The U.N. estimates that 8 million tons of plastic trash are dumped into the world's oceans each year, he said.The Associated Press contributed to this report.